In the heart of China’s energy sector, a pressing challenge has emerged: the mountains of coal-based solid waste that have accumulated over decades of mining and processing. These waste materials, while often overlooked, pose significant environmental risks and occupy vast land resources. However, a recent study published in *Meitan kexue jishu* (translated as *Coal Science and Technology*) offers a beacon of hope, outlining innovative pathways for the large-scale, green, and low-carbon utilization of these wastes.
Lead author Lang Liu, from the College of Energy and Mining Engineering at Xi’an University of Science and Technology, and his team have reclassified coal-based solid waste into two main categories: denatured and original. Denatured waste, which has undergone chemical or physical changes, can be transformed into cementing materials and even used for carbon sequestration. Original waste, on the other hand, retains the characteristics of natural aggregates and soil materials, making it suitable for various construction and ecological restoration projects.
The study highlights several mature large-scale utilization models already in practice. “Mine backfilling is one of the most effective ways to utilize coal-based solid waste,” Liu explains. “By turning these wastes into cementing materials, paste backfilling, or grout backfilling, we can not only fill mined-out areas but also stabilize the ground and prevent subsidence.”
Beyond mine backfilling, the research identifies other promising avenues. Coal-based solid waste can be repurposed as supplementary cementitious materials, road materials, and precast components for construction. Additionally, it can be used in ecological restoration projects, such as filling subsidence areas, reclaiming wastelands, and improving soil quality. The waste can also be a source of valuable resources, including carbonaceous components, aluminum, sulfur, and rare elements.
One of the most innovative aspects of the study is the proposal for a graded, quality-specific, and full-component utilization technology. This approach involves extracting high-value components from the waste and using the remaining materials for backfilling mined-out areas. “This method maximizes resource utilization and minimizes waste,” Liu notes. “It’s a win-win situation for both the environment and the economy.”
The study also explores innovative technologies for modifying and co-disposing of high-salinity wastewater, modifying backfill for co-constructing storage facilities, and co-sequestering hazardous solid waste in functional storage. These advancements could significantly enhance the resource utilization efficiency of bulk coal-based solid waste and promote the green transformation of the coal industry.
The implications of this research are far-reaching. As the energy sector grapples with the dual challenges of meeting growing demand and reducing environmental impact, the large-scale utilization of coal-based solid waste offers a promising solution. By turning waste into valuable resources, the coal industry can not only mitigate its environmental footprint but also unlock new economic opportunities.
“Our goal is to provide new pathways for the sustainable development of coal resources,” Liu concludes. “By embracing green and low-carbon technologies, we can ensure that coal continues to play a vital role in China’s energy mix while safeguarding our environment for future generations.”
As the world watches China’s energy sector evolve, the insights from this study could inspire similar initiatives globally, shaping the future of coal utilization and paving the way for a more sustainable energy landscape.